Social dominance in beef cattle — A scoping review

Validation of proximity loggers to record proximity events among beef bulls

Social behavior in cattle can be measured by how often and for how long they interact with each other. This information can be used to guide management decisions, identify sick animals, or model the spread of diseases. However, visual observation of proximity events is time-demanding and challenging, especially for rangeland cattle spread over a large area. Although proximity loggers can potentially overcome these challenges remotely, it is unknown how accurate these devices are in recording proximity events among beef bulls. The objectives of this study were: 1) to determine the accuracy of Lotek LiteTrack LR collars with built-in proximity loggers to identify proximity events among bulls and 2) to determine the accuracy of Lotek LiteTrack LR collars to identify proximity events between bulls wearing collars and bulls wearing the Lotek V7E 154D ear tag proximity transmitter. Collars were deployed in 12 bulls in 2021 (Experiment 1), and 10 bulls (5 collars and 5 ear tags) in 2023 (Experiment 2). Videos were recorded of bull behavior in both years to compare proximity observed to proximity recorded by the loggers. Sensitivity (Se), specificity (Sp), precision (Pr), and accuracy (Ac) were calculated after computing true positives (TP), false positives (FP), false negatives (FN), and true negatives (TN). The interquartile range method was used to detect outliers. As collars work as both a transmitter and receiver in Exp. 1, reciprocity was assessed by the Concordance Correlation Coefficient (CCC) as an indirect measure of reliability. In Exp. 1, most observations were TN (95.13%), followed by FN (4.11%), TP (0.70%), and FP (0.06%). A high Sp (median = 1.0; 95% CI = 1.0 to 1.0), Pr (1.00; 0.72 to 1.0), and Ac (0.96; 0.95 to 0.97), and low Se (0.10; 0.06 to 0.21) were observed. A high reciprocity agreement (0.93; 0.89 to 0.96) was also observed. Likewise, in Exp. 2 most observations were TN (85.05%), followed by FN (9.94%), TP (4.36%), and FP (0.65%), while high Sp (0.99; 0.99 to 1.0), Pr (0.89; 0.80 to 0.92), and Ac (0.95; 0.81 to 0.95), and low Se (0.35; 0.24 to 0.61) was observed. The Pr of two loggers in Exp. 1 and Pr and Ac of one logger in Exp. 2 were considered outliers. In conclusion, both proximity loggers demonstrated high precision, specificity, and accuracy but low sensitivity in recording proximity among beef bulls. Therefore, these characteristics should be considered when deciding whether to use these devices or not.

Positive Correlation of Social Rank and Hair Cortisol Concentration in Group-Housed Pregnant Cows

In intensive beef production systems, social dominance relationships among cattle and human-cattle relationships constantly affect cattle welfare. However, these factors have not been investigated to assess their long-term effects on cattle welfare. In this study, the relations of hair cortisol concentrations of group-housed pregnant cows with their social rank and avoidance distance when approached by humans were analysed. Thirty-two Japanese black cows were used in this study. Examinations were conducted six times throughout two years, and each cow was subjected to one-three examinations. Hair sampling was conducted on each examination day. The hair cortisol concentrations were measured using a cortisol enzyme immunoassay kit. Social behaviour recordings were made about 6 h on each examination day. The numbers of occurrences of butt, threat, chase, and avoidance behaviours of each animal were recorded using continuous recording methods, and the social rank score for each animal was calculated from the data. Avoidance distances from humans approaching were measured for 23 test cows during the first three examination days. Measurements were taken 5-10 min after the start of morning feeding. The relations between the hair cortisol concentration and social rank score or avoidance distance were analysed using a mixed-effects model or correlation analysis. Significant positive correlation was found between the social rank score and hair cortisol concentration (F1, 48 = 4.54, p = 0.038). No significant correlation was found between the cows' responsiveness to humans and their hair cortisol concentration (r = -0.004, p = 0.99, n = 23). The findings suggest that low-ranking cows had lower cortisol levels.

Social rank affects the endocrine response to frequent regroupings in grazing dairy heifers

The objectives of this study were to determine the social behavior response to repeated social regrouping (SR), and if social rank and the changes of social rank affect the growth rate and some metabolites and hormones linked to energy status, in "resident" replacement dairy heifers subjected to SR for 205 d. Fourteen dairy heifers (153.3 ± 16.1 kg; 9 to 11 mo old), maintained under grazing conditions, were regrouped every 21 d with 5 new animals (total = 10 SR). Two days after each SR, heifers were weighed and their withers height was measured, and blood samples for nonesterified fatty acids, glucose, and IGF-1 were taken. Concentrations of nonesterified fatty acids, glucose, and IGF-1 were taken. Social behavior was registered by continuous sampling and social status was calculated by the ETlog software, considering the total number of agonistic interactions on 2 d before and 7 d after each SR. A dominance scale was constructed in each SR, and heifers were categorized as high-ranked (HRA), medium-ranked (MRA), and low-ranked (LRA). In addition, the social rank in the first and the last 5 SR were compared, resulting in 3 categories: heifers that remained in the same social rank (Mai), and heifers that lowered (Low) and raised (Rai) their social ranks. Variables were analyzed by repeated measures using a generalized lineal mixed model, considering the social rank in each SR or the change in social rank, the number of SR and their interaction as main effects, and the farm of origin and animal as random effects. Heifers performed more agonistic (2.6 vs. 1.8 ± 0.6, day of SR and 7 d later, respectively) and total (3.8 ± 1.2 vs. 2.5 ± 0.7, day of SR and 7 d later, respectively) interactions on the day of each SR than 7 d after, whereas the number of interactions decreased after the first 2 SR. Medium-ranked heifers presented greater IGF-1 concentrations than HRA heifers at SR1, SR4, and SR9, and than LRA heifers at SR3 and SR4, whereas IGF-1 concentrations were greater in HRA heifers than MRA heifers at SR3 and SR7. In addition, LRA heifers had greater IGF-1 concentrations than MRA ones at SR3 and compared with HRA heifers at SR9. Heifers that lowered their social had greater IGF-1 concentrations than Mai heifers along the SR (132.5 ± 17.1 vs. 97.8 ± 11.2 ng/mL, Low and Mai heifers, respectively) and at SR1, SR3, and SR9. In conclusion, although regrouping animals according to their characteristics can facilitate farm handling, it should be considered that endocrine profile may be affected according to heifers' position in the social hierarchy.

Spatial Distribution and Hierarchical Behaviour of Cattle Using a Virtual Fence System

Interest in virtual fencing has increased due to its flexibility for agriculture and rewilding. However, systems like Nofence© require large financial investments, and the need for individual collars complicates large-scale use. If cattle herds maintain cohesive groups around leading individuals, fewer collars could be used, thereby enhancing cost efficiency. This study investigates the pattern in spatial distribution in a herd of 17 Angus cows on Fanø in Denmark with GPS locations, using a Nofence© system. The aim of this paper is to determine how individuals position themselves in a herd, spatially, and identify a pattern in ranks. The method used in this study examines the distances between an individual to the rest of the herdmates using nearest neighbour and descriptive statistics. Contrary to expectations, this study did not reveal a distinct pattern in herd distribution. While some tendencies in spatial distribution patterns were observed, only a low concordance could be found (W=0.15,p<0.001), indicating great variability in the cattle's ranks. A cumulative curve of the ranks estimated over the entire periods, however, allowed a rough estimation of the hierarchy and allowed identification of the highest-ranked cows, making the use of a cumulative curve a possible solution to finding the high-ranked cows. This research underscores the complexity of cattle social structures and highlights the need for extended observation periods and alternative methodologies to enhance the cost-effectiveness and scalability of virtual fencing in agricultural and rewilding contexts.

Social effects on behaviorally-scored and pedometer-detected estrus in beef cattle

The number of cows in estrus often influences estrus behavior; however, the effects of social order are not well documented. This study examined the effects of social order on the expression of behaviorally-scored and pedometer-detected estrus, combined with the effects of the number of cows in estrus. In a herd comprising 13 or 15 beef cattle, cows with orders 1st-7th were defined as dominant and the remaining cows as subordinate. Sole or simultaneous estrus was induced by prostaglandin F2α analog injection and/or intravaginal progesterone treatment. Ovulation timing was determined using ultrasonography at 6-hour intervals. Estrous signs and steps of the cows were recorded 49 h before ovulation using video monitoring and a pedometer, respectively. Among the 59 treated cows, 56 behaviorally-scored estruses (27 sole and 29 simultaneous) were detected. In the sole estrus, 61.5% of the dominant-rank cows had no zero-point period; however, 35.7% of the subordinate-rank cows had that period. The dominant-rank cows in estrus alone had a significantly shorter duration of scored estrus than those in simultaneous estrus (P < 0.05). Among the 50 pedometer-detected estruses (24 sole and 26 simultaneous), the subordinate-rank cows in sole estrus had a shorter interval from estrus onset to ovulation than the dominant-rank cows in simultaneous estrus (P < 0.05). The effects of social order varied in response to the number of cows in estrus, which might have influenced determining the optimal time for artificial insemination.

The Effectiveness of Virtual Fencing of Bull Calves in a Holistic Grazing System

Large grazers are essential for nature conservation. In order to prevent grazers from moving to unintended areas, it may be necessary to keep them inside enclosures. Physical fences present a number of problems, such as fragmenting the landscape. Virtual fencing, however, is a possible replacement for physical fencing, making it possible to enclose grazers without physical boundaries. Virtual fencing systems utilise collars with GPS technology to track animals and deliver auditory warnings and electric impulses to keep animals within predefined boundaries. This study examines how effective the virtual fencing system Nofence© is at enclosing calves in a holistically managed setting. Holistic management is a rotational grazing technique where an enclosure is grazed in small strips at a time. It is investigated whether the calves become habituated to the virtual fence and whether there is a correlation between the number of warnings received by every two calves in order to explore potential herd behaviour. Finally, this study examines which calves interact the most with the virtual fence by investigating the relationship between physical activity and number of interactions. Seventeen calves were fitted with a GPS collar from the company Nofence© and placed in a holistically managed enclosure. Data were gathered from 4 July to 30 September 2022. The study found that virtual fence was able to contain calves inside the designated enclosure, and over time the calves received notably fewer electrical impulses compared to auditory warnings. The results of Pearson's correlation between auditory warnings received by two random calves were inconclusive, but the use of a sliding window analysis should be further explored. Lastly, the most physically active animals were the ones who received the most auditory warnings, but they did not receive more impulses. No significant correlation was found between the number of electric impulses received and the physical activity of the animals.

Using Expert Elicitation for ranking hazards, promoters and animal-based measures for on-farm welfare assessment of indoor reared beef cattle: an Italian experience

On-farm welfare assessment gives the opportunity to monitor and improve the quality of the animal life on the farm. In order to build the first Italian public standard for the welfare of indoor reared beef cattle, a list of 25 potential hazards and 22 potential promoters of beef cattle welfare was judged by a group of national experts by taking into account their negative or positive impacts on the welfare-state of the target population. In addition, the experts were asked to rank a list of 11 animal-based measures for identifying the most appropriate and important for measuring negative welfare outcomes in beef cattle. Based on experts' ratings, an "impact score" (IS_overall) was calculated for the proposed measures. Management hazards and promoters were ranked to have a greater impact on beef cattle welfare than housing factors. Keeping cattle in large (≥ 40 animals) and heterogeneous groups obtained the highest IS_overall among the proposed hazards (IS_overall = 5.54), followed by the presence of animals without free access to drinking water (IS_overall = 4.39) and the use of high-concentrate corn silage diets (concentrate > 80% and fiber < 6%) (IS_overall = 4.39). On the other hand, housing animals in small (≤ 20 animals) and homogeneous groups (IS_overall = 5.41), checking them at least twice a day (IS_overall = 4.62) and rearing cattle in loose housing systems with access to an outdoor area/pasture (IS_overall = 4.27) were ranked among the top 3 promoters. Concerning animal-based measures, experts scored lameness, severe respiratory diseases, body condition scoring and mortality rate to be measures most important for assessing serious welfare impairment.

Glucocorticoids of European Bison in Relation to Their Status: Age, Dominance, Social Centrality and Leadership

Stress is the body's response to cope with the environment and generally better survive unless too much chronic stress persists. While some studies suggest that it would be more stressful to be the dominant individual of the group, others support the opposite hypothesis. Several variables can actually affect this relationship, or even cancel it. This study therefore aims to make the link between social status and the basal level of stress of 14 wild European bison (Bison bonasus, L. 1758) living together. We collected faeces and measured the faecal glucocorticoid metabolites (FGM). We showed that FGM is linked to different variables of social status of European bison, specifically age, dominance rank, eigenvector centrality but also to interactions between the variables. Preferential leaders in bison, i.e., the older and more dominant individuals which are more central ones, are less stressed compared to other group members. Measurement of such variables could thus be a valuable tool to follow and improve the conservation of species by collecting data on FGM and other social variables and adapt group composition or environmental conditions (e.g., supplement in food) according to the FGM concentration of herd individuals.